Peel the kohlrabi and cut into fine cubes. Melt the butter in a saucepan and sauté the diced kohlrabi briefly. Add the julienne soup vegetables and sauté briefly. Dust with flour and stir well. Pour in the vegetable stock, loosen the stoving and let simmer gently for about 10 minutes. Season with salt and pepper, sprinkle with chives or parsley and finely chopped kohlrabi leaves before serving.